Recently, gene therapies for treating severe genetic diseases, cancers and the like have been developed. Most of the gene therapies which have been examined for clinical application to humans heretofore involve gene transfer into cells using recombinant retroviral vectors. The retroviral vector can stably integrate a foreign gene of interest into chromosomal DNA of target cells. Therefore, gene transfer by the retroviral vector is a preferable means of gene transfer particularly for the gene therapy in which long-term gene expression is desired.
It has been reported that the efficiency of gene transfer using a retroviral vector is increased by use of a cell adhesive substance that binds to retroviruses, such as fibronectin or a fibronectin fragment CH-296 [RETRONECTIN® (recombinant human fibronectin fragment)] (e.g., Patent Literature 1). Also, it has been reported that the gene transfer efficiency is further increased by a method comprising adding a solution containing a retroviral vector to a vessel coated with RETRONECTIN® (recombinant human fibronectin fragment) followed by incubation for a certain period of time to allow only the viral vector to bind onto RETRONECTIN® (recombinant human fibronectin fragment), removing a supernatant containing an inhibitory substances against infection, and then adding target cells (RETRONECTIN® Bound Virus Infection Method: RBV method) (Patent Literature 2, Non-Patent Literature 1).
The binding of the viral vector to RETRONECTIN® (recombinant human fibronectin fragment) in the RBV method can be enhanced by utilizing centrifugal force (centrifugal RBV method). However, the centrifugal RBV method requires a vessel that can bear centrifugal force and an expensive apparatus for a centrifugal operation, and the operation includes multi-steps. In addition, there is also a problem that it is difficult to scale up the processing capacity when gene transfer into a large amount of cells is required.